Every few weeks someone publishes a comparison of MCP, A2A, and Pilot Protocol as if you have to pick one. I have seen the charts. One column per protocol, rows for features, checkmarks and crosses. They are almost always wrong, not because the facts are wrong but because the framing is wrong. These three protocols do not compete with each other. They sit at different layers of the same stack. Choosing between them is like choosing between TCP and HTTP. The question does not make sense because one is a transport and one is an application protocol and you need both. Here is where each one actually lives, and why a real multi-agent system will likely end up using all three. MCP: your agent talks to tools Model Context Protocol is Anthropic's specification for how an agent connects to external tools and data sources. An agent holds an MCP client. MCP servers expose tools through a standardized JSON-RPC interface. The agent calls the tool, gets a result, and continues. The mental model is a plugin system.…